// This rule was feature-frozen before we enabled no-property-in-node.
/* eslint-disable eslint-plugin/no-property-in-node */

import type { JSONSchema, TSESLint, TSESTree } from '@typescript-eslint/utils';

import { AST_NODE_TYPES } from '@typescript-eslint/utils';
import naturalCompare from 'natural-compare';

import {
  createRule,
  getNameFromIndexSignature,
  getNameFromMember,
  MemberNameType,
} from '../util';

export type MessageIds =
  | 'incorrectGroupOrder'
  | 'incorrectOrder'
  | 'incorrectRequiredMembersOrder';

type ReadonlyType = 'readonly-field' | 'readonly-signature';

type MemberKind =
  | 'accessor'
  | 'call-signature'
  | 'constructor'
  | 'field'
  | 'get'
  | 'method'
  | 'set'
  | 'signature'
  | 'static-initialization'
  | ReadonlyType;

type DecoratedMemberKind =
  | 'accessor'
  | 'field'
  | 'get'
  | 'method'
  | 'set'
  | Exclude<ReadonlyType, 'readonly-signature'>;

type NonCallableMemberKind = Exclude<
  MemberKind,
  'constructor' | 'readonly-signature' | 'signature'
>;

type MemberScope = 'abstract' | 'instance' | 'static';

type Accessibility = '#private' | TSESTree.Accessibility;

type BaseMemberType =
  | `${Accessibility}-${Exclude<
      MemberKind,
      'readonly-signature' | 'signature' | 'static-initialization'
    >}`
  | `${Accessibility}-${MemberScope}-${NonCallableMemberKind}`
  | `${Accessibility}-decorated-${DecoratedMemberKind}`
  | `${MemberScope}-${NonCallableMemberKind}`
  | `decorated-${DecoratedMemberKind}`
  | MemberKind;

type MemberType = BaseMemberType | BaseMemberType[];

type AlphabeticalOrder =
  | 'alphabetically'
  | 'alphabetically-case-insensitive'
  | 'natural'
  | 'natural-case-insensitive';

type Order = 'as-written' | AlphabeticalOrder;

interface SortedOrderConfig {
  memberTypes?: 'never' | MemberType[];
  optionalityOrder?: OptionalityOrder;
  order?: Order;
}

type OrderConfig = 'never' | MemberType[] | SortedOrderConfig;
type Member = TSESTree.ClassElement | TSESTree.TypeElement;

type OptionalityOrder = 'optional-first' | 'required-first';

export type Options = [
  {
    classes?: OrderConfig;
    classExpressions?: OrderConfig;
    default?: OrderConfig;
    interfaces?: OrderConfig;
    typeLiterals?: OrderConfig;
  },
];

const neverConfig: JSONSchema.JSONSchema4 = {
  type: 'string',
  enum: ['never'],
};

const arrayConfig = (memberTypes: string): JSONSchema.JSONSchema4 => ({
  type: 'array',
  items: {
    oneOf: [
      {
        $ref: memberTypes,
      },
      {
        type: 'array',
        items: {
          $ref: memberTypes,
        },
      },
    ],
  },
});

const objectConfig = (memberTypes: string): JSONSchema.JSONSchema4 => ({
  type: 'object',
  additionalProperties: false,
  properties: {
    memberTypes: {
      oneOf: [arrayConfig(memberTypes), neverConfig],
    },
    optionalityOrder: {
      $ref: '#/items/0/$defs/optionalityOrderOptions',
    },
    order: {
      $ref: '#/items/0/$defs/orderOptions',
    },
  },
});

export const defaultOrder: MemberType[] = [
  // Index signature
  'signature',
  'call-signature',

  // Fields
  'public-static-field',
  'protected-static-field',
  'private-static-field',
  '#private-static-field',

  'public-decorated-field',
  'protected-decorated-field',
  'private-decorated-field',

  'public-instance-field',
  'protected-instance-field',
  'private-instance-field',
  '#private-instance-field',

  'public-abstract-field',
  'protected-abstract-field',

  'public-field',
  'protected-field',
  'private-field',
  '#private-field',

  'static-field',
  'instance-field',
  'abstract-field',

  'decorated-field',

  'field',

  // Static initialization
  'static-initialization',

  // Constructors
  'public-constructor',
  'protected-constructor',
  'private-constructor',

  'constructor',

  // Accessors
  'public-static-accessor',
  'protected-static-accessor',
  'private-static-accessor',
  '#private-static-accessor',

  'public-decorated-accessor',
  'protected-decorated-accessor',
  'private-decorated-accessor',

  'public-instance-accessor',
  'protected-instance-accessor',
  'private-instance-accessor',
  '#private-instance-accessor',

  'public-abstract-accessor',
  'protected-abstract-accessor',

  'public-accessor',
  'protected-accessor',
  'private-accessor',
  '#private-accessor',

  'static-accessor',
  'instance-accessor',
  'abstract-accessor',

  'decorated-accessor',

  'accessor',

  // Getters
  'public-static-get',
  'protected-static-get',
  'private-static-get',
  '#private-static-get',

  'public-decorated-get',
  'protected-decorated-get',
  'private-decorated-get',

  'public-instance-get',
  'protected-instance-get',
  'private-instance-get',
  '#private-instance-get',

  'public-abstract-get',
  'protected-abstract-get',

  'public-get',
  'protected-get',
  'private-get',
  '#private-get',

  'static-get',
  'instance-get',
  'abstract-get',

  'decorated-get',

  'get',

  // Setters
  'public-static-set',
  'protected-static-set',
  'private-static-set',
  '#private-static-set',

  'public-decorated-set',
  'protected-decorated-set',
  'private-decorated-set',

  'public-instance-set',
  'protected-instance-set',
  'private-instance-set',
  '#private-instance-set',

  'public-abstract-set',
  'protected-abstract-set',

  'public-set',
  'protected-set',
  'private-set',
  '#private-set',

  'static-set',
  'instance-set',
  'abstract-set',

  'decorated-set',

  'set',

  // Methods
  'public-static-method',
  'protected-static-method',
  'private-static-method',
  '#private-static-method',

  'public-decorated-method',
  'protected-decorated-method',
  'private-decorated-method',

  'public-instance-method',
  'protected-instance-method',
  'private-instance-method',
  '#private-instance-method',

  'public-abstract-method',
  'protected-abstract-method',

  'public-method',
  'protected-method',
  'private-method',
  '#private-method',

  'static-method',
  'instance-method',
  'abstract-method',

  'decorated-method',

  'method',
];

const allMemberTypes = [
  ...new Set(
    (
      [
        'readonly-signature',
        'signature',
        'readonly-field',
        'field',
        'method',
        'call-signature',
        'constructor',
        'accessor',
        'get',
        'set',
        'static-initialization',
      ] as const
    ).flatMap(type => [
      type,

      ...(['public', 'protected', 'private', '#private'] as const)
        .flatMap<MemberType>(accessibility => [
          type !== 'readonly-signature' &&
          type !== 'signature' &&
          type !== 'static-initialization' &&
          type !== 'call-signature' &&
          !(type === 'constructor' && accessibility === '#private')
            ? `${accessibility}-${type}` // e.g. `public-field`
            : [],

          // Only class instance fields, methods, accessors, get and set can have decorators attached to them
          accessibility !== '#private' &&
          (type === 'readonly-field' ||
            type === 'field' ||
            type === 'method' ||
            type === 'accessor' ||
            type === 'get' ||
            type === 'set')
            ? [`${accessibility}-decorated-${type}`, `decorated-${type}`]
            : [],

          type !== 'constructor' &&
          type !== 'readonly-signature' &&
          type !== 'signature' &&
          type !== 'call-signature'
            ? (
                [
                  'static',
                  'instance',
                  // There is no `static-constructor` or `instance-constructor` or `abstract-constructor`
                  ...(accessibility === '#private' ||
                  accessibility === 'private'
                    ? []
                    : (['abstract'] as const)),
                ] as const
              ).flatMap(
                scope =>
                  [
                    `${scope}-${type}`,
                    `${accessibility}-${scope}-${type}`,
                  ] as const,
              )
            : [],
        ])
        .flat(),
    ]),
  ),
];

const functionExpressions = [
  AST_NODE_TYPES.FunctionExpression,
  AST_NODE_TYPES.ArrowFunctionExpression,
];

/**
 * Gets the node type.
 *
 * @param node the node to be evaluated.
 */
function getNodeType(node: Member): MemberKind | null {
  switch (node.type) {
    case AST_NODE_TYPES.TSAbstractMethodDefinition:
    case AST_NODE_TYPES.MethodDefinition:
    case AST_NODE_TYPES.TSMethodSignature:
      return node.kind;
    case AST_NODE_TYPES.TSCallSignatureDeclaration:
      return 'call-signature';
    case AST_NODE_TYPES.TSConstructSignatureDeclaration:
      return 'constructor';
    case AST_NODE_TYPES.TSAbstractPropertyDefinition:
    case AST_NODE_TYPES.TSPropertySignature:
      return node.readonly ? 'readonly-field' : 'field';
    case AST_NODE_TYPES.TSAbstractAccessorProperty:
    case AST_NODE_TYPES.AccessorProperty:
      return 'accessor';
    case AST_NODE_TYPES.PropertyDefinition:
      return node.value && functionExpressions.includes(node.value.type)
        ? 'method'
        : node.readonly
          ? 'readonly-field'
          : 'field';
    case AST_NODE_TYPES.TSIndexSignature:
      return node.readonly ? 'readonly-signature' : 'signature';
    case AST_NODE_TYPES.StaticBlock:
      return 'static-initialization';
    default:
      return null;
  }
}

/**
 * Gets the raw string value of a member's name
 */
function getMemberRawName(
  member:
    | TSESTree.AccessorProperty
    | TSESTree.MethodDefinition
    | TSESTree.Property
    | TSESTree.PropertyDefinition
    | TSESTree.TSAbstractAccessorProperty
    | TSESTree.TSAbstractMethodDefinition
    | TSESTree.TSAbstractPropertyDefinition
    | TSESTree.TSMethodSignature
    | TSESTree.TSPropertySignature,
  sourceCode: TSESLint.SourceCode,
): string {
  const { name, type } = getNameFromMember(member, sourceCode);

  if (type === MemberNameType.Quoted) {
    return name.slice(1, -1);
  }
  if (type === MemberNameType.Private) {
    return name.slice(1);
  }
  return name;
}

/**
 * Gets the member name based on the member type.
 *
 * @param node the node to be evaluated.
 */
function getMemberName(
  node: Member,
  sourceCode: TSESLint.SourceCode,
): string | null {
  switch (node.type) {
    case AST_NODE_TYPES.TSPropertySignature:
    case AST_NODE_TYPES.TSMethodSignature:
    case AST_NODE_TYPES.TSAbstractAccessorProperty:
    case AST_NODE_TYPES.TSAbstractPropertyDefinition:
    case AST_NODE_TYPES.AccessorProperty:
    case AST_NODE_TYPES.PropertyDefinition:
      return getMemberRawName(node, sourceCode);
    case AST_NODE_TYPES.TSAbstractMethodDefinition:
    case AST_NODE_TYPES.MethodDefinition:
      return node.kind === 'constructor'
        ? 'constructor'
        : getMemberRawName(node, sourceCode);
    case AST_NODE_TYPES.TSConstructSignatureDeclaration:
      return 'new';
    case AST_NODE_TYPES.TSCallSignatureDeclaration:
      return 'call';
    case AST_NODE_TYPES.TSIndexSignature:
      return getNameFromIndexSignature(node);
    case AST_NODE_TYPES.StaticBlock:
      return 'static block';
    default:
      return null;
  }
}

/**
 * Returns true if the member is optional based on the member type.
 *
 * @param node the node to be evaluated.
 *
 * @returns Whether the member is optional, or false if it cannot be optional at all.
 */
function isMemberOptional(node: Member): boolean {
  switch (node.type) {
    case AST_NODE_TYPES.TSPropertySignature:
    case AST_NODE_TYPES.TSMethodSignature:
    case AST_NODE_TYPES.TSAbstractAccessorProperty:
    case AST_NODE_TYPES.TSAbstractPropertyDefinition:
    case AST_NODE_TYPES.AccessorProperty:
    case AST_NODE_TYPES.PropertyDefinition:
    case AST_NODE_TYPES.TSAbstractMethodDefinition:
    case AST_NODE_TYPES.MethodDefinition:
      return node.optional;
  }
  return false;
}

/**
 * Gets the calculated rank using the provided method definition.
 * The algorithm is as follows:
 * - Get the rank based on the accessibility-scope-type name, e.g. public-instance-field
 * - If there is no order for accessibility-scope-type, then strip out the accessibility.
 * - If there is no order for scope-type, then strip out the scope.
 * - If there is no order for type, then return -1
 * @param memberGroups the valid names to be validated.
 * @param orderConfig the current order to be validated.
 *
 * @return Index of the matching member type in the order configuration.
 */
function getRankOrder(
  memberGroups: BaseMemberType[],
  orderConfig: MemberType[],
): number {
  let rank = -1;
  const stack = [...memberGroups]; // Get a copy of the member groups

  while (stack.length > 0 && rank === -1) {
    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
    const memberGroup = stack.shift()!;
    rank = orderConfig.findIndex(memberType =>
      Array.isArray(memberType)
        ? memberType.includes(memberGroup)
        : memberType === memberGroup,
    );
  }

  return rank;
}

function getAccessibility(node: Member): Accessibility {
  if ('accessibility' in node && node.accessibility) {
    return node.accessibility;
  }
  if ('key' in node && node.key.type === AST_NODE_TYPES.PrivateIdentifier) {
    return '#private';
  }
  return 'public';
}

/**
 * Gets the rank of the node given the order.
 * @param node the node to be evaluated.
 * @param orderConfig the current order to be validated.
 * @param supportsModifiers a flag indicating whether the type supports modifiers (scope or accessibility) or not.
 */
function getRank(
  node: Member,
  orderConfig: MemberType[],
  supportsModifiers: boolean,
): number {
  const type = getNodeType(node);

  if (
    node.type === AST_NODE_TYPES.MethodDefinition &&
    node.value.type === AST_NODE_TYPES.TSEmptyBodyFunctionExpression
  ) {
    return -1;
  }

  if (type == null) {
    // shouldn't happen but just in case, put it on the end
    return orderConfig.length - 1;
  }

  const abstract =
    node.type === AST_NODE_TYPES.TSAbstractAccessorProperty ||
    node.type === AST_NODE_TYPES.TSAbstractPropertyDefinition ||
    node.type === AST_NODE_TYPES.TSAbstractMethodDefinition;

  const scope =
    'static' in node && node.static
      ? 'static'
      : abstract
        ? 'abstract'
        : 'instance';
  const accessibility = getAccessibility(node);

  // Collect all existing member groups that apply to this node...
  // (e.g. 'public-instance-field', 'instance-field', 'public-field', 'constructor' etc.)
  const memberGroups: BaseMemberType[] = [];

  if (supportsModifiers) {
    const decorated = 'decorators' in node && node.decorators.length > 0;
    if (
      decorated &&
      (type === 'readonly-field' ||
        type === 'field' ||
        type === 'method' ||
        type === 'accessor' ||
        type === 'get' ||
        type === 'set')
    ) {
      memberGroups.push(`${accessibility}-decorated-${type}`);
      memberGroups.push(`decorated-${type}`);

      if (type === 'readonly-field') {
        memberGroups.push(`${accessibility}-decorated-field`);
        memberGroups.push(`decorated-field`);
      }
    }

    if (
      type !== 'readonly-signature' &&
      type !== 'signature' &&
      type !== 'static-initialization'
    ) {
      if (type !== 'constructor') {
        // Constructors have no scope
        memberGroups.push(`${accessibility}-${scope}-${type}`);
        memberGroups.push(`${scope}-${type}`);

        if (type === 'readonly-field') {
          memberGroups.push(`${accessibility}-${scope}-field`);
          memberGroups.push(`${scope}-field`);
        }
      }

      memberGroups.push(`${accessibility}-${type}`);
      if (type === 'readonly-field') {
        memberGroups.push(`${accessibility}-field`);
      }
    }
  }

  memberGroups.push(type);
  if (type === 'readonly-signature') {
    memberGroups.push('signature');
  } else if (type === 'readonly-field') {
    memberGroups.push('field');
  }

  // ...then get the rank order for those member groups based on the node
  return getRankOrder(memberGroups, orderConfig);
}

/**
 * Groups members into arrays of consecutive members with the same rank.
 * If, for example, the memberSet parameter looks like the following...
 * @example
 * ```
 * interface Foo {
 *   [a: string]: number;
 *
 *   a: x;
 *   B: x;
 *   c: x;
 *
 *   c(): void;
 *   B(): void;
 *   a(): void;
 *
 *   (): Baz;
 *
 *   new (): Bar;
 * }
 * ```
 * ...the resulting array will look like: [[a, B, c], [c, B, a]].
 * @param memberSet The members to be grouped.
 * @param memberType The configured order of member types.
 * @param supportsModifiers It'll get passed to getRank().
 * @returns The array of groups of members.
 */
function groupMembersByType(
  members: Member[],
  memberTypes: MemberType[],
  supportsModifiers: boolean,
): Member[][] {
  const groupedMembers: Member[][] = [];
  const memberRanks = members.map(member =>
    getRank(member, memberTypes, supportsModifiers),
  );
  let previousRank: number | undefined = undefined;
  members.forEach((member, index) => {
    if (index === members.length - 1) {
      return;
    }
    const rankOfCurrentMember = memberRanks[index];
    const rankOfNextMember = memberRanks[index + 1];
    if (rankOfCurrentMember === previousRank) {
      groupedMembers.at(-1)?.push(member);
    } else if (rankOfCurrentMember === rankOfNextMember) {
      groupedMembers.push([member]);
      previousRank = rankOfCurrentMember;
    }
  });
  return groupedMembers;
}

/**
 * Gets the lowest possible rank(s) higher than target.
 * e.g. given the following order:
 *   ...
 *   public-static-method
 *   protected-static-method
 *   private-static-method
 *   public-instance-method
 *   protected-instance-method
 *   private-instance-method
 *   ...
 * and considering that a public-instance-method has already been declared, so ranks contains
 * public-instance-method, then the lowest possible rank for public-static-method is
 * public-instance-method.
 * If a lowest possible rank is a member group, a comma separated list of ranks is returned.
 * @param ranks the existing ranks in the object.
 * @param target the minimum target rank to filter on.
 * @param order the current order to be validated.
 * @returns the name(s) of the lowest possible rank without dashes (-).
 */
function getLowestRank(
  ranks: number[],
  target: number,
  order: MemberType[],
): string {
  let lowest = ranks[ranks.length - 1];

  ranks.forEach(rank => {
    if (rank > target) {
      lowest = Math.min(lowest, rank);
    }
  });

  const lowestRank = order[lowest];
  const lowestRanks = Array.isArray(lowestRank) ? lowestRank : [lowestRank];
  return lowestRanks.map(rank => rank.replaceAll('-', ' ')).join(', ');
}

export default createRule<Options, MessageIds>({
  name: 'member-ordering',
  meta: {
    type: 'suggestion',
    docs: {
      description: 'Require a consistent member declaration order',
      frozen: true,
    },
    messages: {
      incorrectGroupOrder:
        'Member {{name}} should be declared before all {{rank}} definitions.',
      incorrectOrder:
        'Member {{member}} should be declared before member {{beforeMember}}.',
      incorrectRequiredMembersOrder: `Member {{member}} should be declared after all {{optionalOrRequired}} members.`,
    },
    schema: [
      {
        type: 'object',
        $defs: {
          allItems: {
            type: 'string',
            enum: allMemberTypes as string[],
          },
          optionalityOrderOptions: {
            type: 'string',
            enum: ['optional-first', 'required-first'],
          },
          orderOptions: {
            type: 'string',
            enum: [
              'alphabetically',
              'alphabetically-case-insensitive',
              'as-written',
              'natural',
              'natural-case-insensitive',
            ],
          },
          typeItems: {
            type: 'string',
            enum: [
              'readonly-signature',
              'signature',
              'readonly-field',
              'field',
              'method',
              'constructor',
            ],
          },
          // ajv is order-dependent; these configs must come last
          baseConfig: {
            oneOf: [
              neverConfig,
              arrayConfig('#/items/0/$defs/allItems'),
              objectConfig('#/items/0/$defs/allItems'),
            ],
          },
          typesConfig: {
            oneOf: [
              neverConfig,
              arrayConfig('#/items/0/$defs/typeItems'),
              objectConfig('#/items/0/$defs/typeItems'),
            ],
          },
        },
        additionalProperties: false,
        properties: {
          classes: {
            $ref: '#/items/0/$defs/baseConfig',
            description: 'Which ordering to enforce for classes.',
          },
          classExpressions: {
            $ref: '#/items/0/$defs/baseConfig',
            description: 'Which ordering to enforce for classExpressions.',
          },
          default: {
            $ref: '#/items/0/$defs/baseConfig',
            description: 'Which ordering to enforce for default.',
          },
          interfaces: {
            $ref: '#/items/0/$defs/typesConfig',
            description: 'Which ordering to enforce for interfaces.',
          },
          typeLiterals: {
            $ref: '#/items/0/$defs/typesConfig',
            description: 'Which ordering to enforce for typeLiterals.',
          },
        },
      },
    ],
  },
  defaultOptions: [
    {
      default: {
        memberTypes: defaultOrder,
      },
    },
  ],
  create(context, [options]) {
    /**
     * Checks if the member groups are correctly sorted.
     *
     * @param members Members to be validated.
     * @param groupOrder Group order to be validated.
     * @param supportsModifiers A flag indicating whether the type supports modifiers (scope or accessibility) or not.
     *
     * @return Array of member groups or null if one of the groups is not correctly sorted.
     */
    function checkGroupSort(
      members: Member[],
      groupOrder: MemberType[],
      supportsModifiers: boolean,
    ): Member[][] | null {
      const previousRanks: number[] = [];
      const memberGroups: Member[][] = [];
      let isCorrectlySorted = true;

      // Find first member which isn't correctly sorted
      for (const member of members) {
        const rank = getRank(member, groupOrder, supportsModifiers);
        const name = getMemberName(member, context.sourceCode);
        const rankLastMember = previousRanks[previousRanks.length - 1];

        if (rank === -1) {
          continue;
        }

        // Works for 1st item because x < undefined === false for any x (typeof string)
        if (rank < rankLastMember) {
          context.report({
            node: member,
            messageId: 'incorrectGroupOrder',
            data: {
              name,
              rank: getLowestRank(previousRanks, rank, groupOrder),
            },
          });

          isCorrectlySorted = false;
        } else if (rank === rankLastMember) {
          // Same member group --> Push to existing member group array
          memberGroups[memberGroups.length - 1].push(member);
        } else {
          // New member group --> Create new member group array
          previousRanks.push(rank);
          memberGroups.push([member]);
        }
      }

      return isCorrectlySorted ? memberGroups : null;
    }

    /**
     * Checks if the members are alphabetically sorted.
     *
     * @param members Members to be validated.
     * @param order What order the members should be sorted in.
     *
     * @return True if all members are correctly sorted.
     */
    function checkAlphaSort(
      members: Member[],
      order: AlphabeticalOrder,
    ): boolean {
      let previousName = '';
      let isCorrectlySorted = true;

      // Find first member which isn't correctly sorted
      members.forEach(member => {
        const name = getMemberName(member, context.sourceCode);

        // Note: Not all members have names
        if (name) {
          if (naturalOutOfOrder(name, previousName, order)) {
            context.report({
              node: member,
              messageId: 'incorrectOrder',
              data: {
                beforeMember: previousName,
                member: name,
              },
            });

            isCorrectlySorted = false;
          }

          previousName = name;
        }
      });

      return isCorrectlySorted;
    }

    function naturalOutOfOrder(
      name: string,
      previousName: string,
      order: AlphabeticalOrder,
    ): boolean {
      if (name === previousName) {
        return false;
      }

      switch (order) {
        case 'alphabetically':
          return name < previousName;
        case 'alphabetically-case-insensitive':
          return name.toLowerCase() < previousName.toLowerCase();
        case 'natural':
          return naturalCompare(name, previousName) !== 1;
        case 'natural-case-insensitive':
          return (
            naturalCompare(name.toLowerCase(), previousName.toLowerCase()) !== 1
          );
      }
    }

    /**
     * Checks if the order of optional and required members is correct based
     * on the given 'required' parameter.
     *
     * @param members Members to be validated.
     * @param optionalityOrder Where to place optional members, if not intermixed.
     *
     * @return True if all required and optional members are correctly sorted.
     */
    function checkRequiredOrder(
      members: Member[],
      optionalityOrder: OptionalityOrder | undefined,
    ): boolean {
      const switchIndex = members.findIndex(
        (member, i) =>
          i && isMemberOptional(member) !== isMemberOptional(members[i - 1]),
      );

      const report = (member: Member): void =>
        context.report({
          loc: member.loc,
          messageId: 'incorrectRequiredMembersOrder',
          data: {
            member: getMemberName(member, context.sourceCode),
            optionalOrRequired:
              optionalityOrder === 'required-first' ? 'required' : 'optional',
          },
        });

      // if the optionality of the first item is correct (based on optionalityOrder)
      // then the first 0 inclusive to switchIndex exclusive members all
      // have the correct optionality
      if (
        isMemberOptional(members[0]) !==
        (optionalityOrder === 'optional-first')
      ) {
        report(members[0]);
        return false;
      }

      for (let i = switchIndex + 1; i < members.length; i++) {
        if (
          isMemberOptional(members[i]) !==
          isMemberOptional(members[switchIndex])
        ) {
          report(members[switchIndex]);
          return false;
        }
      }

      return true;
    }

    /**
     * Validates if all members are correctly sorted.
     *
     * @param members Members to be validated.
     * @param orderConfig Order config to be validated.
     * @param supportsModifiers A flag indicating whether the type supports modifiers (scope or accessibility) or not.
     */
    function validateMembersOrder(
      members: Member[],
      orderConfig: OrderConfig,
      supportsModifiers: boolean,
    ): void {
      if (orderConfig === 'never') {
        return;
      }

      // Standardize config
      let order: Order | undefined;
      let memberTypes: string | MemberType[] | undefined;
      let optionalityOrder: OptionalityOrder | undefined;

      /**
       * It runs an alphabetic sort on the groups of the members of the class in the source code.
       * @param memberSet The members in the class of the source code on which the grouping operation will be performed.
       */
      const checkAlphaSortForAllMembers = (memberSet: Member[]): undefined => {
        const hasAlphaSort = !!(order && order !== 'as-written');
        if (hasAlphaSort && Array.isArray(memberTypes)) {
          groupMembersByType(memberSet, memberTypes, supportsModifiers).forEach(
            members => {
              checkAlphaSort(members, order as AlphabeticalOrder);
            },
          );
        }
      };

      // returns true if everything is good and false if an error was reported
      const checkOrder = (memberSet: Member[]): boolean => {
        const hasAlphaSort = !!(order && order !== 'as-written');

        // Check order
        if (Array.isArray(memberTypes)) {
          const grouped = checkGroupSort(
            memberSet,
            memberTypes,
            supportsModifiers,
          );

          if (grouped == null) {
            checkAlphaSortForAllMembers(members);
            return false;
          }

          if (hasAlphaSort) {
            grouped.map(groupMember =>
              checkAlphaSort(groupMember, order as AlphabeticalOrder),
            );
          }
        } else if (hasAlphaSort) {
          return checkAlphaSort(memberSet, order as AlphabeticalOrder);
        }

        return false;
      };

      if (Array.isArray(orderConfig)) {
        memberTypes = orderConfig;
      } else {
        order = orderConfig.order;
        memberTypes = orderConfig.memberTypes;
        optionalityOrder = orderConfig.optionalityOrder;
      }

      if (!optionalityOrder) {
        checkOrder(members);
        return;
      }

      const switchIndex = members.findIndex(
        (member, i) =>
          i && isMemberOptional(member) !== isMemberOptional(members[i - 1]),
      );

      if (switchIndex !== -1) {
        if (!checkRequiredOrder(members, optionalityOrder)) {
          return;
        }
        checkOrder(members.slice(0, switchIndex));
        checkOrder(members.slice(switchIndex));
      } else {
        checkOrder(members);
      }
    }

    // https://github.com/typescript-eslint/typescript-eslint/issues/5439
    /* eslint-disable @typescript-eslint/no-non-null-assertion */
    return {
      ClassDeclaration(node): void {
        validateMembersOrder(
          node.body.body,
          options.classes ?? options.default!,
          true,
        );
      },
      'ClassDeclaration, FunctionDeclaration'(node): void {
        if ('superClass' in node) {
          // ...
        }
      },
      ClassExpression(node): void {
        validateMembersOrder(
          node.body.body,
          options.classExpressions ?? options.default!,
          true,
        );
      },
      TSInterfaceDeclaration(node): void {
        validateMembersOrder(
          node.body.body,
          options.interfaces ?? options.default!,
          false,
        );
      },
      TSTypeLiteral(node): void {
        validateMembersOrder(
          node.members,
          options.typeLiterals ?? options.default!,
          false,
        );
      },
    };
    /* eslint-enable @typescript-eslint/no-non-null-assertion */
  },
});
